CNI with flannel
Flannel is a simple, lightweight layer 3 fabric for Kubernetes. Flannel manages an IPv4 network between multiple nodes in a cluster. It does not control how containers are networked to the host, only how the traffic is transported between hosts. For more complicated scenarios, see also Calico and Canal.
Deploying Charmed Kubernetes with Flannel
To deploy a cluster with Flannel, deploy the charmed-kubernetes bundle with the
flannel overlay:
juju deploy charmed-kubernetes --overlay flannel-overlay.yaml
You can apply any additional customisation overlays that would apply to
charmed-kubernetes to this deployment as well.
Flannel options
| Name | Type | Default value | Description |
|---|---|---|---|
| cidr | string | 10.1.0.0/16 | Network CIDR to assign to Flannel |
| iface | string | see description> | The interface to bind flannel overlay networking. The default value is the interface bound to the CNI endpoint. |
| nagios_context | string | juju | A string that will be prepended to instance name to set the host name in nagios. If you’re running multiple environments with the same services in them this allows you to differentiate between them. Used by the nrpe subordinate charm. |
| nagios_servicegroups | string | (empty) | A comma-separated list of nagios servicegroups. If left empty, the nagios_context will be used as the servicegroup |
Checking the current configuration
To check the current configuration settings for Flannel, run the command:
juju config flannel
Setting a config option
To set an option, simply run the config command with an additional <key>=<value> argument. For example, to set a specific network CIDR:
juju config flannel cidr="10.5.0.0/16"
Troubleshooting
If there is an issue with connectivity, it can be useful to inspect the Juju logs. To see a complete set of logs for flannel:
juju debug-log --replay --include=flannel
For additional troubleshooting pointers, please see the dedicated troubleshooting page.